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Single crystals of Na2Cu+[Cu2+3O](AsO4)2Cl (1) and Cu3[Cu3O]2(PO4)4Cl2 (2) were prepared by chemical vapor transport reactions. Both crystal structures are based upon the same [O2Cu6]8+ chains formed by corner-sharing (OCu4)6+ tetrahedra and interconnected by (TO4)3− (T = P, As) tetrahedra into porous {[OCu3](TO4)2Cl}3− frameworks. The channels within the frameworks are occupied by Na+, Cu+ and Cl− ions in the crystal structure of 1, whereas the channels in the structure of 2 contain edge-sharing CuO4Cl tetragonal pyramids. Both compounds are structurally related to the previously described synthetic Na2Cu+[Cu2+3O](PO4)2Cl and NaCu2+[Cu2+3O](PO4)2Cl. The compound 2 is structurally and chemically related to yaroshevskite, Cu3[Cu3O]2(VO4)4Cl2, a mineral discovered in volcanic fumaroles, but the two structure types are drastically different. The crystal chemical analysis of the title and related compounds allows to recognize a family of at least four compounds based upon {[OCu3](TO4)2Cl}3− frameworks with channels occupied by different chemical constituents. [ABSTRACT FROM AUTHOR]

The crystal structure of sergeysmirnovite, MgZn2(PO4)2·4H2O (orthorhombic, Pnma, a = 10.6286(4), b = 18.3700(6), c = 5.02060(15) Å, V = 980.26(6) Å3, Z = 4), a new member of the hopeite group of minerals, was determined and refined to R1 = 0.030 using crystals from the Këster mineral deposit in Sakha-Yakutia, Russia. Similar to other members of the hopeite group, the crystal structure of sergeysmirnovite is based upon [Zn(PO4)]– layers interlinked via interstitial [MO2(H2O)4]2– octahedra, where M = Mg2+. The layers are parallel to the (010) plane. Within the layer, the ZnO4 tetrahedra share common corners to form chains running along [001]. Sergeysmirnovite is a dimorph of reaphookhillite, a mineral from the Reaphook Hill zinc deposit in South Australia. The relations between sergeysmirnovite and reaphookhillite are the same as those between hopeite and parahopeite. Topological and structural complexity analysis using information theory shows that the hopeite (sergeysmirnovite) structure type is more complex, both structurally and topologically, than the parahopeite (reaphookhillite) structure type. Such complexity relations contradict the general observation that more complex polymorphs possess higher physical density and higher stability, since parahopeite is denser than hopeite. It could be hypothesized that hopeite is metastable under ambient conditions and separated from parahopeite by a structural and topological reconstruction that requires an essential energy barrier that is difficult to overcome. [ABSTRACT FROM AUTHOR]

Ivanyukite-Na-T, [Na.sub.3][[Ti.sub.4](OH)[O.sub.3](Si[O.sub.4]).sub.3]]*7[H.sub.2]O, ivanyukite-Na-C, [Na.sub.2][[Ti.sub.4][O.sub.2][(OH).sub.2](Si[O.sub.4]).sub.3]] * 6[H.sub.2]O, ivanyukite-K, [K.sub.2][[Ti.sub.4][(OH).sub.2][O.sub.2](Si[O.sub.4]).sub.3]] * 9[H.sub.2]O, and ivanyukite-Cu, Cu[[Ti.sub.4][(OH).sub.2][O.sub.2] [(Si[O.sub.4]).sub.3]] * 7[H.sub.2]O, are new microporous titanosilicates found in a natrolitized microcline-aegirine-sodalite lens in the orthoclase-bearing urtite at the Koashva Mountain (Khibiny Massif, Kola Peninsula, Russia). The minerals occur as well-shaped colorless (ivanyukite-Na-T), paleorange (ivanyukite-Na-C), pale-blue (ivanyukite-K), and green (ivanyukite-Cu) cubic crystals (up to 1.5 mm in diameter) grown on mierocline, vinogradovite, sazykinaite-(Y), natrolite, and djerfisherite. The minerals have vitreous luster and white streak. They are transparent and non-fluorescent. The Mohs hardness is estimated as ~4. The minerals are brittle. Cleavage is perfect on {100} (ivanyukite-Na-C, ivanyukite-K, and ivanyukite-Cu) or on {1011} (ivanyukite-Na-T), fracture is steppe& Density, measured by the sink/float method in heavy liquids, ranges from 2.60 (ivanyukite-Na-C) to 2.70 g/[cm.sup.3] (ivanyukite-Na-T, ivanyukite-K, and ivanyukite-Cu), whereas calculated densities are: 2.58 (ivanyukite-Na-T), 2.39 (ivanyukite-Na-C), 2.69 (ivanyukite-K), and 2.46 g/[cm.sup.3] (ivanyukiteCu). Ivanyukite-Na-T is uniaxial (+), [n.sub.[omega]] = 1.76(1), [n.sub.[epsilon]] = 1.85(9) (589 nm), and the other minerals are isotropie, n = 1.73(1). Chemical analysis by electron microprobe gave (wt% for ivanyukite-Na-T, ivanyukite-Na-C, ivanyukite-K, and ivanyukite-Cu, respeetively): [Na.sub.2]O 7.46, 5.19, 0.27, and 0.17; [Al.sub.2][O.sub.3] 0.07, 0.21, 0.18, and 0.07; Si[O.sub.2] 23.75, 25.47, 23.16, and 24.80; S[O.sub.3] 0.00, 0.00, 0.00, and 0.20; [K.sub.2]O 5.89, 6.34, 7.09, and 6.81; CaO 0.21, 0.14, 0.95, and 0.23; Ti[O.sub.2] 38.89, 37.81, 36.14, and 38.36; MnO 0.05, 0.33, 0.68, and 0.28; FeO 0.54, 2.17, 0.37, and 0.73; CuO 0.00, 0.00, 2.21, and 6.81; SrO 0.00, 0.00, 0.19, and 0.00; [Nb.sub.2][O.sub.5] 2.99, 2.90, 3.62, and 3.02; BaO 0.14, 0.00, 0.00, and 0.00; [H.sub.2]O (by the Penfield method) 19.00, 19.15, 25.00, and 21.50; total 98.99, 99.71, 99.86, and 98.97. The empirical formulae (based on Si+Al = 3 apfu) are [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII.] 7.21[H.sub.2]O (ivanyukite-Cu). Ivanyukite-Na-T is trigonal, R3m, a = 10.94(2), c = 13.97(4) [Angstrom], Z = 3. Other minerals are cubie, P43m a = 7.856(6) (ivanyukite-Na-C), 7.808(2) (ivanyukite-K), and 7.850(7) [Angstrom] (ivanyukite-Cu); Z = 1. The strongest lines in the powder X-ray diffraetion pattern [[d.sub.bs]([Angstrom]) ([I.sub.obs]) hkl] are: 7.88(100) (011), 3.277(60)(014), 3.175(80)(212), 2.730(50)(220), 2.607(70)(303), 2.471(50)(124), 1.960(60)(044), 1.916(50) (135) (ivanyukite-Na-T); 7.88(100)(100), 4.53(30)(111), 3.205(80)(211), 2.774(30)(220), 2.622(40)(221,300), 2.478(40)(310), 1.960(30)(400), 1.843(30)(330, 411) (ivanyukite-Na-C); 7.85(100)(100), 3.91(20)(200), 3.201(80) (211), 2.765(20)(220), 2.602(30)(221,300), 2.471(40)(310), 1.951(30)(400), 1.839(30)(330, 411) (ivanyukite-K); 7.87(100)(100), 3.94(20)(200), 3.205(80)(211), 2.774(20)(220), 2.616(30)(221, 300), 2.481(30)(310), 1.960(30) (400), 1.843(30)(330, 411) (ivanyukite-Cu). The crystal structure ofivanyukite-Na-T [trigonal, R3m, a = 10.921(3), c = 13.885(4) [Angstrom], V = 1434.2(7) [[Angstrom].sup.3]] has been solved from highly mosaic crystal and refined to [R.sub.1] = 0.147 on the basis of 723 unique observed reflections. The crystal structures of ivanyukite-group minerals are based upon a 3-dimensional framework of the pharmacosiderite type, consisting of four edge-sharing Ti[O.sub.6]-octahedra interlinked by Si[O.sub.4] tetrahedra. The framework has a 3-dimensional system of channels defined by 8-membered rings with an effective channel width of 3.5 [Angstrom] (caleulated as the distance between O atoms across the channels minus 2.7 [Angstrom]). The channels are occupied by [Na.sup.+] and [K.sup.+] cations and [H.sub.2]O molecules. The infrared spectra of the ivanyukite group minerals show 14 absorption bands caused by vibrations of Si-O and Ti-O bonds, molecular water, and [(OH).sup.-] groups. Ivanyukite Na-T formed as a late-stage, hydrothermal phase of ultra-agpaitic hydrothermalites; ivanyukite-Na-C is produced by partial hydration of ivanyukite-Na-T, and both ivanyukite-K and ivanyukite-Cu are produced by partial hydration of ivanyukite-Na-T and natural cation exchange of Cu for Na near dissolved djerfisherite and chalcopyrite grains. Nomenclature of the ivanyukite group is based on the dominant extraframework cation and symmetry of the crystal structure. The minerals are named in honor of Gregory Yur'evich Ivanyuk, Russian mineralogist and petrologist, head of the Laboratory of Self-Organized Mineral Systems in the Geological Institute of the Kola Science Centre of the Russian Academy of Sciences, for his contributions to the petrology and mineralogy of banded iron-formations, alkaline, and alkaline-ultrabasic massifs. Keywords: Ivanyukite-Na-T, ivanyukite-Na-C, ivanyukite-K, ivanyukite-Cu, new mineral, microporous titanosilicate, crystal structure, ultra-alkaline hydrothermalite, cation exchange, Khibiny massif, Kola Peninsula

Yakovenchukite-(Y), [K.sub.3]NaCa[Y.sub.2][[Si.sub.12][O.sub.30]][([H.sub.2]O).sub.4], is a new REE silicate found in a thin (3-4 cm) sodalite-aegirine-microcline veinlet cutting ijolite-urtite at Mt. Kukisvumchorr, Khibiny alkaline massif, Kola Peninsula, Russia. The mineral occurs as small prismatic crystals in intimate association with microcline, aegirine, calcite, catapleiite, donnayite-(Y), fluorapophyllite, fluorite, galena, lead, litharge, molybdenite, natrolite-gonnardite, pyrochlore, rinkite, strontianite, and vuorijarvite-K. Yakovenchukite-(Y) is creamy to colorless, with vitreous luster. The streak is white. The mineral is transparent, non-fluorescent. The Mohs hardness is about 5. The mineral is brittle. Cleavage is perfect on {100}, distinct on {010}, fracture is stepped. Densities are 2.83 g/[cm.sup.3] (measured by sink/float in heavy liquids) and 2.72 g/[cm.sup.3] (calculated). Yakovenchukite-(Y) is biaxial (+): [n.sub.[alpha]] = 1.520(5), [n.sub.[beta]] = 1.525(5), [n.sub.[gamma]] = 1.538(5) (589 nm), 2 V(meas.) = 60 [+ or -] 5[degrees], 2V(calc.) = 61.86[degrees]. The optical orientation is Y = c, X = a, Z = b, pleochroism is not observed. Chemical analysis by electron microprobe (wt%): [Na.sub.2]O 4.32, [K.sub.2]O 10.73, CaO 3.42, [Y.sub.2][O.sub.3] 15.49, [Ce.sub.2][O.sub.3] 0.10, [Dy.sub.2][O.sub.3] 0.68, [Er.sub.2][O.sub.3] 0.88, [Tm.sub.2][O.sub.3] 0.18, [Yb.sub.2][O.sub.3] 1.53, Th[O.sub.2] 0.62, Si[O.sub.2] 57.55, [H.sub.2]O (by the Penfield method) 4.70, total 100.20. The empirical formula (based on Si = 12 apfu) is [([K.sub.2.85][Na.sub.0.15]).sub.[SIGMA]3.00][Na.sub.100][([Ca.sub.0.71] [Na.sub.0.00]).sub.[SIGMA]1.31[([Y.sub.1.72] [Yb.sub.0.10][Er.sub.0.06][Dy.sub.0.05][Th.sub.0.03][Ce.sub.0.01] [Tm.sub.0.01][Ca.sub.0.05]).sub.[SIGMA]2.03 [[Si.sub.12][O.sub.30.02]] x 3.27 [H.sub.2]O. According to single-crystal X-ray study yakovenchukite-(Y) is orthorhombic, Pcca, a = 14.972(8), b = 14.137(7), c = 14.594(8) [Angstrom], V = 3089(3) [[Angstrom].sup.3], Z = 4. The strongest lines of the X-ray powder diffraction pattern ate [[d.sub.bs]([Angstrom])([I.sub.obs])(hkl)]: 7.00 (40) (020), 6.57 (60) (102), 4.20 (50) (222), 3.337 (100) (331), 3.248 (90) (024), 3.101 (40) (142), 3.014 (80) (422), 2.608 (40) (404). The crystal structure of yakovenchukite-(Y) belongs to a new structure type of minerals and inorganic compounds. It is based on microporous octahedral-tetrahedral framework of Si[O.sub.4]-tetrahedra and Y[O.sub.6]-octahedra. Silicate tetrahedra share corners to form unprecedented [[Si.sub.l2][O.sub.30]] sheets consisting of 4-, 6-, and 14-membered rings. The sheets are parallel to (001) and are linked into 3D framework through Y[O.sub.6] octahedra. [Ca.sup.2+], [K.sup.+], and [Na.sup.+] cations are located within the framework cavities. The octahedral-tetrahedral framework possess channels extended along the a axis. The channel dimensions are 4.9 x 6.2 [Angstrom], which means the free crystallographic diameter of 2.2 x 3.5 [Angstrom], that allows classifying yakovenchukite-(Y) as a microporous material. Yakovenchukite-(Y) is the latest low-temperature hydrothermal mineral, formed by alteration of earlier REE-rich minerals (pyrochlore, rinkite, etc.). The mineral is named in honor of Victor N. Yakovenchuk, a mineralogist at the Geological Institute of the Kola Science Centre of the Russian Academy of Sciences, for his outstanding contribution to the mineralogy of alkaline and alkaline-ultrabasic massifs. Keywords: Yakovenchukite-(Y), new mineral, REE-silicate, crystal structure, ultra-alkaline hydrothermal vein, Khibiny massif, Kola Peninsula

The crystal structures of the 1M and 2M polytypes of tyrolite have been solved from single-crystal X-ray diffraction data. The structure of tyrolite-1M [monoclinic, P2/c, a = 27.562(3), b = 5.5682(7), c = 10.4662(15) [Angstrom], [beta] = 98.074(11)[degrees], V = 1590.3(3) [[Angstrom].sup.3] has been refined to [R.sub.1] = 0.086 on the basis of 2522 unique observed reflections collected using synchrotron radiation at the Swiss-Norwegian beamline BM01 of the European Synchrotron Research Facility (SNBL at the ESRF). The structure of tyrolite-2M [monoclinic, C2/c, a = 54.520(6), b = 5.5638(6), c = 10.4647(10) [Angstrom] [beta] = 96.432(9)[degrees], V = 3154.4(6) [[Angstrom].sup.3]] has been refined to [R.sub.1] = 0.144 on the basis of 2666 unique observed reflections obtained from a non-merohedrally twinned crystal using in-house X-ray radiation and a STOE IPDS II image-plate diffractometer. The structures are based upon complex nanolayers consisting of Cu, As, and Ca coordination polyhedra. The core of the nanolayer is a copper arsenate substructure consisting of A and B sublayers. The B sublayer consists of chains of edge-sharing Cu octahedra running along the b axis. The A sublayer contains trimeric units of Cu octahedra sharing corners with As[O.sub.4] tetrahedra. Two adjacent A sublayers are linked by the octahedral chains of the B sublayer resulting in formation of the 18 [Angstrom] thick ABA slab. The ABA slab is sandwiched between sublayers of [Ca.sup.2+] cations and [H.sub.2]O molecules. Adjacent nanolayers are connected by hydrogen bonds to the interlayer species (carbonate anions and [H.sub.2]O molecules). The structures of tyrolite-1M and tyrolite-2M differ by the stacking sequence of the nanolayers only. The adjacent nanolayers in tyrolite-2M are shifted by b/2 = 2.8 [Angstrom] in comparison to the relative position of the nanolayers in tyrolite-1M. The structural formula of tyrolite can be written as [[Ca.sub.2][Cu.sub.9] [(As[O.sub.4]).sub.4][(OH).sub.8](C[O.sub.3])[([H.sub.2]O).sub.11]] [([H.sub.2]O).sub.x] where x = 0-1. Keywords: Tyrolite, 'clinotyrolite,' crystal structure, copper arsenate, nanolayers, polytypes

Chivruaiite is a new Ca titanosilicate [orthorhombic, Cmmm, a = 7.17(2), b = 22.98(9), c = 6.94(2) [Angstrom], V = 1144.4 [[Angstrom].sup.3], Z = 1], chemically and structurally related to zorite. The mineral is found in three different hydrothermal veins within the Khibiny and Lovozero alkaline massifs, Kola Peninsula, Russia. It is associated with microcline, eudialyte, natrolite, astrophyllite, aegirine, etc. Chivruaiite occurs as elongate-prismatic crystals (up to 3 mm long) with {100}, {010}, {001}, {101}, and {011} as dominant faces, as well as radiating aggregates. The mineral is transparent, pale-pink to colorless, with vitreous luster and white streak. Cleavage is distinct on {100} and {010}; fracture is step-like. Mohs hardness is about 3. In transmitted light, the mineral is pale-pink, with a faint pleochroism: Z = pale-pink, on X and Y = colorless; dispersion r < v. Chivruaiite is biaxial (+): [alpha] = 1.705(5), [beta] = 1.627(2), [gamma] = 1.612(2) (for [lambda] = 589 nm), 2[V.sub.meas] = 40 [+ or -] 5[degrees], 2[V.sub.calc] = 31.7[degrees]. Optical orientation: X = b, Y = a, Z = c, [D.sub.cale] = 2.42 g/[cm.sup.3], [D.sub.meas] = 2.40-2.42 g/[cm.sup.3]. The mean chemical composition determined by electron microprobe is (wt%): Si[O.sub.2] 45.14; Ti[O.sub.2] 20.63; [Al.sub.2][O.sub.3] 0.07; [Fe.sub.2][O.sub.3] 0.18; MnO 0.02; MgO 0.01; CaO 10.53; [Na.sub.2]O 0.10; [K.sub.2]O 1.30; SrO 0.28; [Nb.sub.2][O.sub.5] 3.63; [H.sub.2]O 17.30; sum. 99.19. Empirical formula calculated on the basis of Si = 12 is [([Ca.sub.3.00][K.sub.0.44][Na.sub.0.05][Sr.sub.0.04] [Mn.sub.0.01]).sub.[SIGMA]=3.54] [([Ti.sub.4.13][Nb.sub.0.44] [Fe.sup.3+.sub.0.04][Al.sub.0.02]).sub.[SIGMA]=4.63][Si.sub.12] [O.sub.34]|[(OH).sub.4.51][O.sub.0.49]] * 13.08[H.sub.2]O. Simplified formula is [Ca.sub.4][(Ti,Nb).sub.5][[([Si.sub.6][O.sub.17]).sub.2]|[(OH,O).sub.5]] * 13-14[H.sub.2]O. The strongest X-ray powder-diffraction lines [d in [Angstrom], (I), (hkl)] are 11.6 (100) (020), 6.91 (90) (110, 001), 5.23 (50) (130), 3.41 (50) (220), 3.35 (50) (061, 151), 3.04 (80) (221, 240). The structure of chivruaiite was refined to [R.sub.1] = 0.038 on the basis of 687 unique observed reflections. It is based upon an open framework of Si[O.sub.4] tetrahedra, Ti[O.sub.6], octahedra, and Ti[O.sub.5] pyramids. Framework cavities are occupied by [Ca.sup.2+] and [K.sup.+] cations, and [H.sub.2]O molecules. The mineral is named after its type locality in the Chivruai River valley (the Lovozero massif, Kola Peninsula, Russia). Chivruaiite is a Ca-analog of zorite and ETS-4 and is closely related to haineaultite. Keywords: Chivruaiite, zorite, titanosilicate, new mineral, crystal structure, Kola Peninsula

The structure of shafranovskirt, ideally [K.sub.2][Na.sub.3] [(Mn,Fe,Na).sub.4] [Si.sub.9][(O.OH).sub.27]][[(OH).sub.2]*n[H.sub.2]O (n ~ 2.33), a K-Na-manganese hydrous silicate from Kola peninsula. Russia, was studied using synchrotron X-ray radiation and a MAR345 image plate detector at tile Swiss-Norwegian beamline of the European Synchrotron Radiation Facility (ESRF, Grenoble, France). The structure [trigonal, space group P3lc, a = 14.519(3), c = 21.062(6) [Angstrom]. V = 3844.9(14) [[Angstrom].sup.3]] was solved by direct methods and partially refined to [R.sub.1] = 0.085 (w[R.sub.2] = 0.238) on the basis of 2243 unique observed refleclions (|[F.sub.0]l [greater than or equal to]2[[sigma].sub.f] Shafranovskite is a 2:1 hydrous phyllosilicate. Sheets of Mn and Na octahedra (O sheets) are sandwiched between two silicate tetrahedral sheets ([T.sub.1] and [T.sub.1]). The 2:1 layers are parallel to (001 ). The upper tetrahedral sheet T, consists of isolated [[Si.sub.3] [(O.OH).sub.3]-] islands composed of three six-membered rings. The octahedral sheet O consists of Mn[[phi].sub.6] Na1[[[phi].sub.6] and Na2[[phi].sub.6], octahedra ([phi] = O, OH, [H.sub.2]O). This unit can be considered as a trioctahedral sheet with each 20th octahedron vacant. The lower tetrahedral sheet [T.sub.2] consists of [[Si.sub.13] [(O, OH).sub.37]] island linked into a sheet through an additional Si[O.sub.3]OH tetrahedron. The Na3, K1, K2 atoms, and [H.sub.2]O32 groups are between the 2:1 layers and provide their linkage along c.

The average crystal structures of two natural porous titanosilicates of the labuntsovite group, lemmleinite-Ba and lemmleinite-K, ideally [Na.sub.4][K.sub.4][Ba.sub.2][Ti.sub.8][([Si.sub.4][O.sub.12]).sub.4] [O.sub.4][(OH).sub.4]*8[H.sub.2]O and [Na.sub.4][K.sub.4][K.sub.2] [Ti.sub.8][([Si.sub.4][O.sub.12]).sub.4][O.sub.2][(OH).sub.6]*8 [H.sub.2]O, respectively, have been refined from single crystal X-ray diffraction data. Both samples represent an extensive solid solution with labuntsovite sensu strictu [Na.sub.4][K.sub.4][D.sub.2][Ti.sub.8] [([Si.sub.4][O.sub.2]).sub.4][O.sub.4][(OH).sub.4]*10[H.sub.2]O where D = Mn, Fe, and Mg. In addition to the sharp Bragg reflections both crystals, space group C2/m, a = 14.3, b =13.8, c = 7.75 [Angstrom], [beta] = 117[degrees], exhibit diffuse layers at c*/2 intervals indicating faulty superstructures with c = 15.7 [Angstrom]. The diffuse layers consist of two types of reflections. The dominant type is strongly diffuse and smeared along a* indicating an I-centered Bravais lattice. The other type is very sharp but also weak and is in agreement with a C-centered lattice. Models for both superstructures have been developed on the basis of crystal-chemical principles and their theoretical diffraction patterns have been calculated and compared with the observed diffuse layers yielding excellent qualitative agreement. X-ray structure refinements of the average structure at -160 and 22 [degrees]C indicate temperature independent (static) disorder of Ti within rather rigid Ti[O.sub.6] octahedra connected to chains that extend along a. This Ti disorder is interpreted in terms of long-range order of OH and O in the superstructures where these anions occupy the corner-connecting octahedral apices in an ordered fashion. An additional effect of OH, O order is an ordered arrangement of extraframework Ba (K) that only bonds to O but not to OH sites exposed on the channel walls. Temperature dependent cell dimensions between -160 and +200 [degrees]C suggest a phase transition at ca. -80 [degrees]C. However, the structural data obtained from the average structures, refined at -160 and 22 [degrees]C, did not allow us to draw crystal-chemical conclusions about the nature of the phase transition. Dehydration of the investigated lemmleinite-Ba starts at ca. 150 [degrees]C leading to increasing extraframework disorder and decreasing crystal quality as evidenced by strong smearing of the originally sharp Bragg reflections.

The crystal structure of yuksporite. [(Sr.Ba).sub.2] [K.sub.4][(Ca,Na).sub.14]([cube root],Mn,Fe){[(Ti,Nb).sub.4][(O.OH).sub.4][[Si.sub.6] [O.sub.17].sub.2][[Si.sub.2] [O.sub.7].sub.3]}[(H.sub.2][O.OH).sub.n], where n ~ 3 [monoclinic. P[2.sub.1]/m, a = 7.126(3). b = 24.913(6). c = 17.075(7) [Angstrom]. [beta] = 101.89(3)[degrees], V=2966.4(17) [Angstrom].sup.3] has been solved using X-ray synchrotron radiation data collected from a needle-like crystal with dimensions of 6 x 6 x 50 [micro][m.sup.3] at the Swiss-Norwegian beamline BM01 of the European Synchrotron Research Facility (ESRF. Grenoble, France). The structure was refined to [R.sub.1] = 0.101 on the basis of 2359 unique observed reflections with |F [sub.0]| [greater than or equal to] 4[[sigma].sub.f]. The structure of yuksporite is based upon titanosilicate nanorods elongated along a and with an elliptical cross-section of ca. 16 x 19 [Angstrom] = 1.6 x 1.9 nm. Silicate tetrahedra form double xonotlite-like chains [sup.1.sub.[infinity]] [[Si.sub.6][O.sub.17]] oriented parallel to (00l). Two [sup.1.[infinity][[Si.sub.6][O.sub.17]] chains are linked into a rod via Ti[O.sub.6] octahedra and [Si.sub.2][O.sub.7] double tetrahedra. The {[(Ti.Nb).sub.4][(O.OH).sub.4][[[Si.sub.6][O.sub.17]].sub.2] [[[Si.sub.2][O.sub.7]].sub.3]} nanorods are porous. The internal pores are defined by eight-membered rings (SMR) with open diameters of 3.2 [Angstrom]. The interior of the titanosilicate nanorods is occupied by St, Ba. K. and Na cations and [H.sub.2]O molecules. The nanorods are separated by walls of Ca coordination polyhedra that are parallel to (010) and link the rods into a three-dimensional structure.

The crystal structure of glagolevite, Na[(Mg,Al).sub.6][[Si.sub.3]Al[O.sub.10]][(OH,O).sub.8], a new mineral from the Kovdor alkaline massif, Kola peninsula, Russia, has been solved and refined to [R.sub.1] = 0.117, calculated from 1503 unique observed reflections ([F.sub.o] [greater than or equal to] 4[sigma][F.sub.o]), and to [R.sub.1] = 0.118 for all 1550 unique reflections. The specimen contained several polytypes; the crystal studied yielded triclinic space group C1, a = 5.3580(11), b = 9.2810(19), c = 14.574(3) [Angstrom], [alpha] = 90.00(3), [beta] = 97.08(3), [gamma] = 90.00(3)[degrees], V = 719.2(3) [[Angstrom].sup.3]. Glagolevite is the first mineral of the chlorite group that contains Na atoms located between the 2:1 layers and the interlayer octahedral sheets. The Na atoms are in sevenfold coordination. The Na[(O,OH).sub.7] polyhedron is a trigonal prism with one of the triangular bases extended to a square. The tetrahedral sheets show disorder owing to polytype intergrowths. Tetrahedral site occupancies correlate with the occupancies of the Na sites. The polytypic composition of the crystal studied is estimated at 57% IIb-6, 31% IIb-2, and 12% IIb-4.